Underwater optical positioning systems and methods

ABSTRACT

Systems and methods for positioning objects in underwater environments are provided. The geolocation of a target for an object is determined, and a light source provided as part of a positioning system is operated to project a visible target at that location. The determination of the target location relative to the positioning system can include determining a location of the positioning system using information obtained from a laser system included in the positioning system. The light source used to project the visible target can be the same as a light source included in the laser system. A location of an object relative to the target location can be tracked by the laser system as the object is being moved towards the target location. The described methods and systems utilize one or more non-touch subsea optical systems, including but not limited to laser systems, for underwater infrastructure installation, measurements and monitoring.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/031,812, filed Jul. 10, 2018, which claims the benefit of U.S.Provisional Patent Application Ser. No. 62/530,747, filed Jul. 10, 2017,the entire disclosures of which are hereby incorporated herein byreference.

FIELD

The present disclosure is directed to methods and systems fordetermining and facilitating the positioning of objects underwater.

BACKGROUND

The installation of underwater equipment, such as wellheads, manifolds,risers, anchors, Pipeline End Terminations (PLETS), Blow Out Preventors(BOPs), subsea production systems, touch down points, suction piles,chains, slip joints, concrete mats, and pipelines on the seafloor can bedifficult, and improper installation is costly on many fronts. Often,underwater equipment is installed using specialty surface vessels fittedwith remotely operated vehicles (ROVs) and cranes. The operator is oftenphysically removed from the actual installation area, resulting in alack of spatial awareness. Because of the difficulties inherent topositioning equipment in an underwater environment, placing suchequipment with desired levels of precision is difficult. In addition,particularly where the equipment is being installed in a fieldcontaining other equipment or is being positioned for connection toequipment already in place, there is a risk of damage due to collisions.

Current installation techniques involve the use of an acoustic beacon,which is mounted on the object or structure to be installed along withan ultra-short baseline (USBL) or long baseline (LBL) array, often aidedby inertial navigation, to provide location information to a craneoperator at the surface. The location information (X, Y, Z position andheading) is transmitted to the surface through an acoustic communicationmethod either directly to the surface vessel or via underwater vehicle.The operator is provided with a display of data, for example in the formof range and heading information, regarding placement of the equipment.However, the location information is very coarse (measured in feet) andthe feedback is slow due to the acoustic link.

Once the object is located within visual range of physical marker buoysor a physical boundary box on the seabed, the placement operationswitches to visual placement. The physical marker buoys are positionedusing the same USBL or LBL acoustic array. The operator uses remotevideo in order to determine the positioning of equipment during finalinstallation. The inherent issue with video is it only provides 2-Dinformation. In addition, video systems can be compromised or evenrendered useless by turbid water conditions. In addition, evenrelatively sophisticated video systems can suffer from limited fields ofview, unnatural perspectives, distortion, lighting limitations, andlimited depth of field. Also, existing systems have had only a limitedability to provide absolute location information, or locationinformation relative to emplaced structures.

In addition, the information is not easily translated to an exactlocation within an imaged area of the underwater environment. Analternate technique uses an ROV to track the structure using videocameras as it is being lowered. However, this provides very coarsealignment and positioning information regarding the structure, and theposition of the structure being positioned relative to other structuresis difficult to determine.

In some situations it is possible to use divers or operators insubmersible vehicles for installing equipment. However, even when anoperator has a direct line of sight during the installation process,their view of the scene can be obstructed or obscured. In addition,absolute and relative location data available to operators usingprevious techniques remains limited.

Accordingly, it would be desirable to provide systems and methods thatprovided accurate and useful information to assist operators orautomated systems in positioning equipment in underwater environments.

SUMMARY

The present disclosure provides devices, systems and methods for use inthe positioning of equipment, vehicles, or other objects in underwaterenvironments. Positioning systems in accordance with embodiments of thepresent disclosure can include one or more metrology or monitoringsystems, and one or more projection systems. In accordance with at leastsome embodiments of the present disclosure, the positioning system caninclude an integrated monitoring and projection system. In operation, amonitoring system component of the positioning system determines atarget location for an object, and a projection system component of thepositioning system projects a visible target for use in positioning theobject.

In accordance with embodiments of the present disclosure, a monitoringsystem included in a positioning system can comprise an active,light-based metrology system or sensor. In accordance with at least someembodiments of the present disclosure, a monitoring system includes alight detection and ranging system (hereinafter “lidar”) monitoringdevice. In such embodiments, the lidar device can be in the form of ascanning lidar, flash lidar, pulsed laser lidar, amplitude modulatedcontinuous wave (AMCW) phase detection lidar, chirped AMCW lidar,amplitude frequency modulated continuous wave (FMCW) lidar, true FMCWlidar, pulse modulation code, or other lidar system. Moreover, the lidarsystem can incorporate a pulsed or modulated continuous wave laser lightsource. Other embodiments can include a monitoring system incorporatinga laser triangulation, photometric stereo, stereoscopic vision,structured light, photoclinometry, stereo-photoclinometry, holographic,digital holographic, or other device that uses light to sense 3-D space.The monitoring system is placed in the vicinity of the object beingpositioned. In accordance with embodiments of the present disclosure,multiple pieces of equipment or other objects can be monitored by asingle monitoring system simultaneously. In accordance with furtherembodiments of the present disclosure, multiple monitoring systems areused in combination to monitor one or more pieces of subsea equipment.

A projection system included in a positioning system in accordance withembodiments of the present disclosure includes a light source and apointing or scanning device. In accordance with at least someembodiments of the present disclosure, the monitoring system isintegrated with the projection system. Alternatively, the projectionsystem can be provided separately from the monitoring system. Whetherintegrated with or provided separately from the monitoring system, theprojection system can receive location information from the monitoringsystem that is applied by the projection system to project a visibletarget at a desired location. In accordance with still otherembodiments, the visible target can be provided in various forms.Moreover, the visible target can comprise or can be supplemented withvarious indicia, including target lines, scales, range, depth,coordinates, time, proximity warnings, or the like.

Methods in accordance with embodiments of the present disclosure includedetermining a desired target location for an object. This can includegeolocating the desired location within an absolute reference frame ordetermining the target location relative to other underwater objects orfeatures. A visible target is then projected, to demarcate the targetlocation to an operator. In accordance with at least some embodiments ofthe present disclosure, the visible target can be projected inconsideration of a point of view of the operator or of a camera used toprovide a view of the scene to an operator who is located remotely. Inaccordance with still other embodiments, the projection can becontinuously updated, for example to account for movement in the pointof view of the operator, or to assist the operator in avoiding contactbetween the object being positioned and underwater structures while theobject is being moved towards its target location.

In operation for installation measurements, the positioning system isplaced on the seabed in the vicinity of the structure to be installed.The positioning system is then geolocated. Underwater geolocation istypically performed with acoustic beacons or an Inertial NavigationSystem (INS). The positioning system can then be operated to project avisible target, such as a target box or pattern, on the seafloor or on aselected object. In accordance with embodiments of the presentdisclosure, the location of the projected target is a predeterminedgeolocation. Moreover, the projected target can have a predeterminedorientation. In accordance with further embodiments of the presentdisclosure, the location of the projected target is selected by a user,with a position and heading relative to the geolocation of themonitoring device. In addition, the target location of the object to beplaced or installed can be determined with reference to geo-locatedmonuments or other references. In accordance with at least someembodiments of the present disclosure, the projected target is a targetbox demarcating an area in which an object is to be placed.

Advantages of embodiments of the present disclosure over conventionalsystems and methods for positioning objects in underwater environmentsinclude providing high precision location information from a flexible,agile system, without requiring the installation of physical markers. Inaddition, embodiments of the present disclosure can provide an easilyperceived marker for facilitating the accurate placement of objects inunderwater environments. The described methods and devices increase theaccuracy and efficiency of installation and monitoring capability duringinstallation, drilling, and general construction.

Additional features and advantages of embodiments of the presentdisclosure will become more readily apparent from the followingdescription, particularly when taken together with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an example of an underwater environment in which systemsand methods in accordance with embodiments of the present disclosure canbe employed;

FIG. 2 depicts objects being positioned in an underwater environmentwith the assistance of a positioning system in accordance withembodiments of the present disclosure;

FIG. 3 depicts a positioning system in accordance with embodiments ofthe present disclosure;

FIGS. 4A and 4B are block diagrams depicting functional components ofpositioning systems in accordance with embodiments of the presentdisclosure;

FIG. 5 is a block diagram depicting a monitoring and control station inaccordance with embodiments of the present disclosure;

FIG. 6 depicts a user interface presented in connection with theoperation of a system in accordance with embodiments of the presentdisclosure;

FIG. 7 depicts an undersea scenario including the monitoring of alocation of an object and the projection of a visible target by apositioning system in accordance with embodiments of the presentdisclosure;

FIG. 8 depicts an undersea scenario including the monitoring oflocations of multiple objects and the projection of visible targets bymultiple positioning systems in accordance with embodiments of thepresent disclosure;

FIG. 9 is a flowchart depicting aspects of a process for positioning anobject in an underwater target location in accordance with embodimentsof the present disclosure;

FIG. 10 depicts an undersea scenario including the monitoring of alocation of an object and the projection of a visible target by apositioning system in accordance with other embodiments of the presentdisclosure;

FIG. 11 is a flowchart depicting aspects of a process for positioning anobject in an underwater target location in accordance with otherembodiments of the present disclosure;

FIG. 12 depicts an undersea scenario including the monitoring of alocation of an object and the projection of a visible target by apositioning system in accordance with other embodiments of the presentdisclosure; and

FIG. 13 is a flowchart depicting aspects of a process for positioning anobject in an underwater target location in accordance with otherembodiments of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure provide systems and methods thatcan be used in connection with the placement of objects in underwaterenvironments. FIG. 1 depicts a drilling and production system 100, whichis an example of an environment in which embodiments of the presentdisclosure can be employed. The drilling and production system 100 caninclude a variety of surface and subsea or underwater components. Asexamples, and without limitation, these can include processing platforms104, jack-up platforms 108, floating platforms 112, pipelay vessels 116,pipelines 120, risers 124, manifolds 128, wells 130, touch down points135, suction piles or anchors 136, chain 137, slip joints 138 andblowout preventers 132. As can be appreciated by one of skill in theart, the various components of the system 100 often need to bepositioned with a high level of accuracy, to enable intended functionsto be performed, to operatively connect to other components, and/or toavoid interfering with the operation of other underwater components.

FIG. 2 depicts an underwater environment in which a positioning system200 in accordance with embodiments of the present disclosure can beemployed to assist in placing an object at a target location 202. Inparticular, one or more positioning systems 200 are depicted, mounted toor associated with a platform 224, or carried by a submersible vehicle216. The positioning systems 200 operate to determine a target location202 of an object 208, and to project an image or target indicia 204 toaid in the positioning of the object 208 at a corresponding targetlocation 202. As described in greater detail elsewhere herein, thelocation or area at which the visible target 204 is projected can bedetermined by an active, light-based metrology or monitoring system,such as a laser system. Moreover, in at least some embodiments of thepresent disclosure, the light source used by a monitoring system is alsoused to generate the projected target 204. In the example of FIG. 2, theunderwater environment includes components of a drilling and productionsystem as depicted in FIG. 1, however, embodiments of the presentdisclosure can be applied to any underwater environment or system.

As shown in this example, the objects 208 can be positioned usingvarious emplacing equipment 210. For instance, a first object 208 a isshown being put into position by a crane 212, a second object 208 b isshown being placed into position by a submersible vehicle 216, and athird object 208 c is shown being placed into position by a diver 220.In each instance, one or more positioning systems 200 a-c are used todetermine the target location for a particular object 208, and toproject the target indicia 204 a-c that serves as a visual aid to anoperator in placing the object 208 at the target location 202 a-c. Theprojected image or target indicia 204 is visible to the operator of theemplacement equipment 210, for example through a video system, or via adirect line of sight between the operator and the target location 202.Accordingly, the positioning system 200 can operate to actively assistthe positioning of objects 208 in an undersea environment. Thepositioning system 200 can also be used to assist with positioning anobject 208 on a stationary structure, or in connection with docking anunderwater vehicle 216 or an object 208 with another underwater vehicle216 or object 208. In accordance with embodiments of the presentdisclosure, target stands 222, geo-located monuments 226, or otherreference points can be included in the scenario and can provideadditional location information to the positioning system 200.

A positioning system 200 in accordance with embodiments of the presentdisclosure is positioned in the vicinity of a target location 202 for anobject 208. The positioning system 200 can be mounted to a stationaryplatform or structure 224. As can be appreciated by one of skill in theart, a positioning system 200 mounted to a stationary platform orstructure 224 has an inherent conical field of regard. By incorporatinga pan and tilt head in the positioning system 200, the field of regardcan be increased to a full 360°, or even to over a hemisphere field ofregard. As can further be appreciated by one of skill in the art afterconsideration of the present disclosure, a positioning system 200 can bemounted to a movable platform or vehicle 216, directly or via a pan andtilt head. As examples, but without limitation, a moveable platform orvehicle 216 can include a frame or cage that is moved by a crane, or avehicle, such as but not limited to an autonomous underwater vehicle(AUV), a remotely operated vehicle (ROV), a submersible vehicle, or thelike. Moreover, a moveable platform or vehicle 216 can be heldstationary, for example by landing the platform or vehicle 216 on theseafloor or other structure, by clamping onto a structure, or by holdingit in a hovering mode, while the positioning system 200 is in operation.As discussed in greater detail elsewhere herein, a monitoring systemcomponent of the positioning system 200 can be operated to scan all orportions of an underwater scene to determine location information, and aprojection system component of the positioning system 200 can beoperated to project the target indicia 204.

In accordance with embodiments of the present disclosure,three-dimensional 240 and/or two-dimensional 244 targets can be fixed tovarious objects in the underwater environment, such as components of adrilling and production system 100, for example, pipelines 120, risers124, manifolds 128, wells 130, touch down points 135, anchors, suctionpiles, pin piles, blowout preventers 132, or other structures, targetstands 222, monuments 226, stationary platforms 224, moveable platformsor vehicles 216, or any other underwater object. As discussed in greaterdetail elsewhere herein, these targets 240, 244 are specificallydesigned to provide control points within an image or within 3-D pointcloud data produced by the monitoring system component of a positioningsystem 200. The inclusion of targets 240, 244 can facilitate theaccurate determination of a target location within an underwaterenvironment.

FIG. 3 depicts a positioning system 200, mounted to a supportingstructure 224, in accordance with at least some embodiments of thepresent disclosure. The positioning system 200 generally includes amonitoring system 304. The monitoring system 304 can comprise active,light based systems, such as one or more lidar devices 308. In theillustrated example, the positioning system 200 includes two lidardevices 308, each of which is associated with a pan and tilt head 312that can be operated to point the associated lidar device 308 along aselected line of sight. Alternatively or in addition to a lidar device308, the positioning system 200 can include other optical metrologysystems. The supporting structure 224 can comprise a frame 316 that isin turn mounted to a stationary pad, a mud mat, another structure on theseabed, or placed directly on the seabed. The frame 316 can be designedto be lowered by a crane from the surface vessel or rig or can bedesigned to be deployed via an ROV. The frame 316 can be lowered using acrane lift 320. The lift 320 can be connected to the remainder of theframe 316 by a hinge so it lowers after deployment. This allows the lift320 to drop out of the field of view of the lidar devices 308. The frame316 can also include ROV manipulator handles 324 to facilitatepositioning the frame 316 using an ROV or AUV. For example, the frame316 can be placed on a monument 226 or other structure. The bottom ofthe frame 316 can have a pin or receptacle, so it can be lowered onto amating receptacle or pin on a structure to enable precise location andalignment. In accordance with other embodiments of the presentdisclosure, the frame 316 may be carried by a vehicle, such as an ROV.In accordance with still other embodiments of the present disclosure, apositioning system 200 can be mounted to a vehicle via a pan and tilthead or can be mounted directly to a vehicle.

In at least some embodiments of the present disclosure, the positioningsystem 200 can itself comprise a subsea system with a platform withnumerous selectable functions. In embodiments in which the positioningsystem 200 includes a support structure or frame 316 that holds multiplelidar devices 308, the lidar devices 308 can be precisely located on thesingle structure so they create a single referenced point cloud. Bymounting the lidar devices 308 on pan and tilt heads 312, they canprovide hemispherical coverage. Cameras and lights 328 can be mounted onthe support structure 316 or the pan and tilt heads 312 to enable theacquisition of visual data along with the lidar data. A hot stab 332 canbe included to enable the positioning system 200 to connect to the localinfrastructure for power and/or communications. The positioning system200 can further include one or more non-optical point sensors, such as aconductivity, temperature, and depth (CTD) device 336. Alternately or inaddition, batteries and a power control system 340 can be included whichallow for long-term autonomous deployment. The positioning system 200can also provide additional capabilities including, but not limited to,data storage and backup, vibration sensors, turbidity sensors, variouschemical sensors, and communication devices. The communication devicescan include RF, optical, or acoustic devices. The communication devicescan communicate with ROVs, AUVs, resident vehicles, other intelligentstructures in the field, or systems on the surface. In accordance withstill other embodiments the positioning system 200 can provide timingsignals (if needed) between multiple sensors to time-synchronize thedata collection of multiple sensors, such as from multiple lidar devices208, cameras 328, CTD 336, sonars, INU, and other devices. A singlepositioning system 200 can provide power, data storage, andcommunications for other positioning systems 200 or lidar devices 308,to support multiple monitoring points of view within an underwaterenvironment.

An acoustic transceiver 344 can be included which enables thepositioning system 200 to be geo-spatially located using an acousticpositioning system. These can include Ultra-Short Baseline (USBL), LongBaseline (LBL) or other acoustic positioning systems. 2-D targets 244can be mounted to the frame 316 or other components of the monitoringsystem, and 3-D targets 240 can be mounted to the frame 316 or othercomponents of the positioning system 200, to facilitate preciselylocating the positioning system 200 within a field.

FIGS. 4A and 4B are block diagrams depicting components of a positioningsystem 200 that may be contained within an underwater pressure vessel402 or co-located with one another in accordance with embodiments of thepresent disclosure. FIG. 4A is different from FIG. 4B in that the latterincludes a separate projection system 406 for generating a projectedtarget 204. As the other components of the depicted positioning systems200 are generally the same, the present description will apply to bothFIGS. 4A and 4B, except where otherwise noted. The positioning system200 includes a lidar device 308 or other monitoring or metrology system,such as but not limited to an optical metrology system. As can beappreciated by one of skill in the art, a lidar device 308 is an activeoptical system that operates by transmitting light towards a target,receiving reflected light from the target, and determining the range tothe target based upon time of flight information determined from theamount of time elapsed between the transmission of light from the lightsource and the time at which the reflected light or return signal isreceived at a receiver. As used herein, a target can include an area orfeature on the sea floor, an object 208, or any other underwaterstructure or feature, including manmade structures and natural featuresor structures, 3-D targets 240 mounted to an underwater structure orplaced on the sea floor, and 2-D targets 244 applied to an underwaterstructure or placed on the sea floor. In addition, the location of apoint on the target from which light is reflected can be locatedrelative to the lidar device 308 in three-dimensional space by combiningthe range information with the known azimuth and elevation informationvia scanner location (e.g. as an azimuth angle and an elevation angle)for scanning lidar devices 308, pixel location for multi-pixel lidardevices 308, or a combination of the two. The fourth dimension, time, isalso recorded so measurements and features can be compared over time.

As can be appreciated by one of skill in the art after consideration ofthe present disclosure, the lidar device 308 enables the positioningsystem 200 to determine locations relative to the positioning system200, or relative to objects within the field of regard of the lidardevice 308, or that otherwise have a known relative location. Moreover,where a reference target 240, 244, monument 226, or other object withinthe field of regard of the lidar device 308 or having a known locationrelative to the positioning system 200 has a known absolute location,the lidar device 308 can determine the absolute location of thepositioning system 200 itself and of the objects 208 within the field ofregard of the positioning system 200. Alternatively or in addition, anavigation system, such as an Inertial Navigation Unit (INU) 403, can beused to provide information regarding the location of the positioningsystem 200, and in turn of objects within the field of regard of thelidar device 308. The INU 403 can be used independently or inconjunction with other positioning systems, including acousticpositioning systems, such as acoustic beacons, super-short baseline(SSBL) systems, ultra-short baseline (USBL) systems, or long baseline(LBL) systems.

The components of the positioning system 200 thus include a light source404. The light produced by the light source 404 can be collimated orvariably focused by optics 408. In accordance with at least someembodiments of the present disclosure, the light source 404 is a pulsedbeam laser. As can be appreciated by one of skill in the art afterconsideration of the present disclosure, the light source 404 canproduce light having a selected wavelength or range of wavelengths. Asan example, but without limitation, the light source 404 may comprise ablue-green laser light source. As a further example, the light source404 may have an output centered at 532 nm. Other wavelengths can also beused, for example to optimize performance in response to various waterconditions. In accordance with still other embodiments, the light source404 may produce non-collimated light. In accordance with still otherembodiments, the light source 404 may be light emitting diode (LED)based, continuous wave (CW) laser based, modulated CW based, structuredlight, or some other light source.

The variable focus optics 408 can include traditional mechanicalfocusing elements, or non-mechanical elements, such as may be providedby fluid lenses, liquid crystal devices, electro-optic devices, andother optical elements. The ability to focus the beam can be used tooptimize signal return for a specific target at a specific range forspecific water conditions. The light can then be adjusted in magnitudeby a variable filter or attenuator 412. This is advantageous forunderwater sensing as the attenuation of seawater or other water bodiescan vary dramatically, thus dramatically changing the return signal,which can strain the dynamic range of the receiver. One method forreducing the required dynamic range of the receiver is to adjust thelight output power from the transmitter. This can be achieved by thevariable attenuator 412. As examples, the variable attenuator 412 caninclude standard neutral density filters, other attenuation filters, orpolarization elements.

The optical train can also include a variable polarization rotator 416.It is known that the polarization of the transmitted light can affectthe backscatter power, which is a source of noise at the lidar device308 receiver. Transmission range can therefore be optimized by adjustingthe polarization rotation of the output light. The variable polarizationrotator 416 can impart any polarization to the output light.

Transmit and receive (Tx/Rx) optics 420 are used to make the sensormonostatic. Monostatic sensors have the distinct advantage of simplifiedscanning as the transmitter and receiver are pointed at the samelocation with the same scanning mechanism, resulting in calibration andreliability performance that is superior to bistatic systems. A scanningdevice 424 can then be used to accurately direct the transmitted beamand the field of view of the receiver simultaneously to a scene througha window 428 in the enclosure 402. The scanning device 424 can include asteering mirror or other beam steering device, such as amicro-electro-mechanical system (MEM), liquid crystal, acousto-optic, orelectro-optic device, for precise control of the pointing of the lightsource and receiver toward a target location 202, such as an underwaterstructure, and at known angles relative to the positioning system 200.

Light reflected from the target is received by the scanning device 424and is split by a beam splitter element included in the Tx/Rx optics420. Light from the Tx/Rx optics 420 is provided to a receive telescope430, which is configured to focus the received light so that it can beimaged onto the sensor elements of a receiver 444 included in thepositioning system 200. In at least some embodiments the receivetelescope 430 collimates the light and it is then focused by focusingoptic 446. A variable polarization rotator 432 can be included tooptimize the signal-to-noise ratio (SNR) of the return signal byselecting the optimal polarization for the hard target return.

A fast shutter 436 is provided to block any stray light from the primarybeam as it exits the window 428, after being directed by the scanningdevice 424. The fast shutter 436 is timed with high speed electronics,which may be implemented by a processor 448, to block the window 428reflection from a transmitted pulse and then open quickly to capturereturns from close targets. Light passed by the fast shutter 436 is thenprovided to the receiver 444. The receiver 444 detects the lightreflected from a target, and timing and intensity information regardingthe received signal is used to create a 3-D point cloud data. Thereceiver 444 thus is an optical sensor or detector, such as aphotodiode, an avalanche photodiode, a photomultiplier tube, a siliconphotomultiplier tube, a Geiger mode avalanche photodiode, charge coupleddevice (CCD) detector, complementary metal oxide semiconductor (CMOS)detector, or other optical detector. It can also include an electronicamplifier and/or thermal control elements and circuitry. In addition,the receiver 444 can include or be associated with a narrow band filterto reduce background light. A focusing optic 446 can be included tofocus received light onto the sensor of the receiver 444. In accordancewith embodiments of the present disclosure, the receiver 444 maycomprise a single or multiple pixel sensor. Information regarding therange to the target is monitored by a processor 448, which controlsand/or has access to information regarding the time at which transmittedlight is output, and the time at which a return signal, comprisingtransmitted light that has been reflected from a target, is received bythe receiver 444. In addition, information from the scanning device 424,from a pan and tilt head 312, and/or the location of a receiving pixelin a lidar device 308 having a multiple pixel sensor as the receiver 444can be used by the processor 448 to determine the azimuth angle andelevation angle to the target. This information can then be combinedwith timing information, and in particular the time at which thetransmitted pulse of light produced by the light source 404 is senttowards the target, and the time that the return signal is received atthe receiver 444. The range measurement determined from the timinginformation can then be applied to obtain a location of the targetrelative to the positioning system 200. As can be appreciated by one ofskill in the art after consideration of the present disclosure, theintensity information obtained by the receiver 444 can be analyzed inconnection with determining, for example, whether the return is from anunderwater structure, water, or a plume of fluid. Moreover, theintensity may be provided from the sensor as a voltage signal.

The processor 448 can include any processor capable of performing orexecuting instructions encoded in system software or firmware 463 storedin data storage or memory 464, such as a general purpose programmableprocessor, controller, Application Specific Integrated Circuit (ASIC),Field Programmable Gate Array (FPGA), or the like. Moreover, theexecution of that software or firmware 463 can control the operation ofthe lidar system 308, including the acquisition of point cloud data thatincludes azimuth angle, elevation angle, intensity, and rangeinformation taken from an underwater scene. In accordance with furtherembodiments of the present disclosure, the execution of the software 463can operate to determine a position of an object 208 and a position of atarget location 202. In accordance with still further embodiments,execution of the software 463 can operate to control at least one of thelight source 404 and a projector 450 to project a visible target 204.Moreover, the software 463 can operate to predict a future location of amoving object 208, to generate and report data regarding the object 208,the target location 202, to exchange information with other positioningsystems, to exchange information with a user interface, server system,or other computing node in communication with the positioning system, orthe like. Different operations of the software 463 can be distributedamongst different programs, applications, or software modules. Theexecution of the software 463 by the processor 448 can be performed inconjunction with the memory 464. Moreover, the function of the memory464 can include the short or long-term storage of timing information,range information, point cloud data generated by the lidar system 308,control point locations, or other control information or generated data.The memory 464 can comprise a solid-state memory, hard disk drive, acombination of memory devices, or the like. The positioning system 200can additionally include various sensors. For example, the positioningsystem 200 can include a CTD device 445 for measuring the conductivity(and thus the salinity), the temperature, and the depth of the water atthe location of the positioning system 200. Because a CTD device 445must be in direct contact with the surrounding water, it can be mountedoutside of or adjacent an aperture in the enclosure 402.

As can be appreciated by one of skill in the art after consideration ofthe present disclosure, the basic components of the lidar system 308 arethe light source 404 and the receiver 444. A positioning system 200 inaccordance with at least some embodiments of the present disclosure, forexample as illustrated in FIG. 4A, can utilize the light source 404 andthe scanning device 424 of the lidar device 308 to generate a visibletarget 204. In accordance with other embodiments of the presentdisclosure, for example as illustrated in FIG. 4B, a positioning system200 can include a separate projection system 406 having a projectorlight source 450 and projector scanning device 452 for generating avisible target 204. In another embodiment a scanning device 452 is notrequired as the projector light source can be a 2-D projector like astandard projector system. The light can be passed through a projectorwindow 456, or through the window 428 provided for the lidar system 308.In accordance with at least some embodiments, the light source 404 ofthe lidar system 308 can be operated in combination with a separateprojector light source 450 to project a visible target 204. Forinstance, the projector light source 450 may provide light in one ormore colors that are not available from the light source 404 included aspart of the lidar system 308.

Embodiments of the present disclosure can include all of the componentsillustrated in FIGS. 4A and/or 4B, additional or alternate components,or a subset of these components. In accordance with embodiments of thepresent disclosure, the range and angle measurements should all becompensated using techniques described in U.S. Pat. Nos. 8,184,276 and8,467,044. The memory 464 can be used for storing the locationinformation, operating instructions, generated data, and the like. Aninput/output or communication interface 468 can be included fortransmitting determined information to a monitoring and control station504 (see FIG. 5) or other system or control center in real-time, nearreal-time, or asynchronously. A power source and distribution bus 472can also be integrated with the positioning system 200. Various elementsof a positioning system 200 as disclosed herein can be provided as or bydiscrete or integrated components. For example, various optical elementsof the lidar system 308 can be formed on a substrate that is bonded tothe semiconductor substrate in which the receiver 444 is formed,creating an integrated chip or package.

FIG. 5 is a block diagram depicting human interface and other componentsthat can be provided as part of or in conjunction with a monitoring andcontrol station 504 associated with an underwater positioning system 200in accordance with embodiments of the present disclosure. The monitoringand control station 504 can be provided as a top-side facility, carriedby a mobile platform, such as a surface ship or a submersible vehicle,mounted to a fixed or stationary platform, such as a productionplatform, or located at an on-shore facility. The monitoring and controlstation 504 facilitates or performs functions that include providingoutput to and receiving input from a user or from an automatedprocessing center. The monitoring and control station 504 generallyincludes a processor 508 and memory 512. In addition, the monitoring andcontrol station 504 can include one or more user input devices 516 andone or more user output devices 520. The monitoring and control station504 also generally includes data storage 524. In addition, acommunication interface 528 can be provided, to support interconnectionof the monitoring and control station 504 to the underwater componentsof the positioning system 200, and/or to other systems. This interface528 can be used as a command and control interface to another autonomousdevice that provides the inputs and reads outputs that replaces humanuser interfaces 516 and 520.

The processor 508 may include a general purpose programmable processoror any other processor capable of performing or executing instructionsencoded in software or firmware. In accordance with other embodiments ofthe present disclosure, the processor 508 may comprise a controller,FPGA, or ASIC capable of performing instructions encoded in logiccircuits. The memory 512 may be used to store programs and/or data, forexample in connection with the execution of code or instructions by theprocessor 508. As examples, the memory 512 may comprise RAM, SDRAM, orother solid-state memory. In general, a user input device 516 isincluded as part of the monitoring and control station 504 that allows auser to input commands, including commands that are transmitted to theunderwater components of the overall monitoring system, to controlaspects of the operation of the positioning system 200. Examples of userinput devices 516 that can be provided as part of the monitoring andcontrol station 504 include a keyboard, keypad, microphone, biometricinput device, touch screen, joy stick, mouse, or other position encodingdevice, or the like. A user output device 520 can, for example, includea display, speaker, indicator lamp, or the like. Moreover, a user inputdevice 516 and a user output device 520 can be integrated, for examplethrough a graphical user interface with a pointing device controlledcursor or a touchscreen display. Like the memory 512, the data storage524 may comprise a solid-state device. Alternatively or in addition, thedata storage 524 may comprise, but is not limited to, a hard disk drive,a tape drive, or other addressable storage device or set of devices.Moreover, the data storage 524 can be provided as an integral componentof the monitoring and control station 504, or as an interconnected datastorage device or system.

The data storage 524 may provide storage for a subsea monitoring systemapplication 532 that operates to present a graphical user interfacethrough the user output device 520, and that presents point cloud data,or data derived from point cloud data, obtained by a positioning system200. The application 532 can further operate to receive control commandsfrom a user through the user input device 516, including commandsselecting target areas or other control points in an underwater scene.In accordance with embodiments of the present disclosure, theapplication 532 can perform various functions autonomously, such asidentifying underwater objects, identifying features on underwaterobjects 208, identifying a centroid of an underwater object or a featureof an underwater object, identifying control points on underwaterobjects, identifying target centroids, monitoring the motion, vibration,and/or temperature parameters of underwater objects, or otheroperations. Such automated operations can be implemented using, forexample, image recognition techniques. The data storage 524 canadditionally provide storage for the selected control points 536, forpoint cloud data 540 generated by operation of a positioning system 200,and for range, vibration, vibration mode, temperature, leak detection,or other measurements or data generated by a positioning system 200. Inaccordance with still other embodiments of the present disclosure, thesystem application 532 can be executed to detect motion, vibration,vibration mode, temperature, changes, features, lack of features, otheranomalies, or leaks instead of or in conjunction with execution of thesystem software 463 by the processor 448 of the positioning system 200.The data storage 524 can also store operating system software 544, andother applications or data.

An example of a user interface 604 presented to a user by a user outputdevice 520 is depicted in FIG. 6. As shown, the user interface 604 caninclude a user input section 608 containing a variety of data entryfields and virtual buttons that can be utilized by a user to entercontrol instructions or data through manipulation of one or more userinput devices 516. The user interface 604 can additionally present animage 612 of the underwater scene generated from the point cloud dataobtained by the initial scan of the scene. The image can include pointcloud data obtained from a single lidar device 308, or that has beenstitched together from multiple lidar devices 308. The image could alsobe a subset or derivative of the point cloud data, such as just theintensity information, or a 2-D image. In addition, the image caninclude a depiction or a 2-D image, such as a video image, of aprojected target 204 associated with a target area 202 for an object208. Accordingly, the user interface 604 in cooperation with a camera328 can comprise a video system. In accordance with at least someembodiments of the present disclosure, the location of the target area202 and the projected target 204 can be modified by the user through theuser input devices 516. Accordingly, the establishment of a target area202 can involve a manual operation, in which a user or operatordetermines the target area 202 with reference to the presented image612. As an alternative, the determination as to whether the intendedunderwater structure is included in the scene can be performed throughautomated processes, such as through the execution of image recognitionsoftware included in or provided separately from the system application532. The user interface can include visual and audible indicators andguides as the object 208 approaches the target area 202, such asdirectional arrows, approach velocity, warning indicators, range,heading, error or deviation, depth, temperature, or any other data ordirectional guidance.

FIG. 7 depicts an undersea scenario including the projection of avisible target or image 204, in this example in the form of a targetbox, by a positioning system 200 in accordance with embodiments of thepresent disclosure. The positioning system 200 can be placed on asupport structure placed on the seabed, carried by an ROV or AUV that isstationary on the seabed, carried by an ROV or AUV that is floating in astation-keeping mode, or otherwise carried or placed in the vicinity ofthe target area 202 for an object 208. Information regarding thelocation of the positioning system 200 can be provided by the INU 403.Alternatively, or in addition, the positioning system 200 can obtaininformation regarding its location by referencing one or moregeo-located monuments 226 or other stationary structures on the seabed,or even by the seabed features themselves. Location information obtainedrelative to the geo-location monuments 226 can replace or besupplemented by the known location of the monitoring system 200,obtained, for example, from an INU 403, or other stationary structureson the seabed such as manifolds 128, wells 130, or suction piles 136, oreven by the seabed features themselves. By determining the desiredtarget location 202 relative to the known location of the positioningsystem 200, the positioning system 200 can project the target indicia204 such that it corresponds to, lies within, or otherwise indicates,through a visually perceptible signal, the desired target location 202.The visible target 204 does not have to be a “box” but can be anyvisually perceptible signal of use to the operator of the emplacementequipment 210.

The positioning system 200 can also monitor the location and orientationof the object 208 as it is being brought towards and placed at thetarget location 202. This monitoring of the object 208 can befacilitated through the placement of reference targets 244 on the object208. As discussed in greater detail elsewhere herein, the referencetargets 244 can identify an associated object 208, a side of the object208, and angle of the object 208 relative to the positioning system 200.In a further embodiment the object 208 could be a pipe or cable laydown.In a still further embodiment the reverse can be performed wherepositioning system 200 is mounted on the object 208 and monitors itslocation relative to monuments 226 or other stationary structures suchas manifolds 128, wells 130, or suction piles 136, for example, havingknown locations. In still further embodiments the object 208 can be amoving object such as an ROV or AUV. The positioning informationcollected by monitoring system 200 can be fed back to an operator of theROV, or to the automated control system of an AUV. The improved positionand heading information can increase the accuracy and decrease the riskof close-up operation to expensive equipment such as valve operation andautomated docking.

In addition to aiding with the positioning of the object 208, at leastsome embodiments of the positioning system 200 can measure and reportthe final touchdown speed, along with the final location (x,y,z,heading, pitch, and roll) of the object 208, and how much these varyfrom the ideal target location 202. Along with this final locationreporting, the seabed around the structure can be scanned for “asdeployed” condition, which can be compared to future scans for scourdetection or dredging.

FIG. 7 also depicts the use of an acoustic transponder 704 and ageo-located monument 226 in accordance with embodiments of the presentdisclosure. The positioning system 200 may reference the geo-locatedmonument 226 to determine a relative position of the positioning system200 and/or the acoustic transponder 704. As shown, the geo-locatedmonument 226 can include indicia, such as a two-dimensional 244 andthree dimensional 240 targets, to assist in determining the location ofthe positioning system 200, and in turn objects 208 and or targetlocations 202, relative to the geo-located monument 226. In accordancewith further embodiments of the present disclosure, the indicia caninclude information uniquely identifying an associated geo-locatedmonument 226. The acoustic transponder 704 may comprise a conventionalacoustic transponder that has been modified to include indicia. Indiciaassociated with an acoustic transponder 704 may comprise referencetargets 240, 244 that can be used as control points for determining arelative location of the acoustic transponder 704. In accordance withfurther embodiments of the present disclosure, the indicia can includeinformation uniquely identifying an associated acoustic transponder 704.

FIG. 8 depicts an undersea scenario including multiple positioningsystems 200 monitoring a position of an object 208 in accordance withembodiments of the present disclosure. Each positioning system 200 maybe geo-located, and each may determine a relative location of the object208. The location information determined by a positioning system 200regarding its location, the location of the object 208, the location ofanother positioning system 200, or the location of any other underwaterobject 208 or feature may be shared with other positioning systems 200.The use of multiple positioning systems 200 can provide redundancy, andcan provide enhanced location accuracy, at least under some conditions.A visible target 204 can be projected by one or more than one of thepositioning systems 200. In addition, as in other embodiments, thelocation information regarding the object 208 can be fed back to theoperator of the lift, crane, vehicle, or other equipment being used toposition the object 208. Moreover, a positioning system 200, or multiplepositioning systems 200, can track multiple objects 208 simultaneouslyor nearly simultaneously, for example by scanning a first one of theobjects to determine a current position of that object 208, scanning asecond object 208 to determine a current position of that object, and soon, before returning to scanning the first object 208. Moreover, avisible target 204 can be projected by a positioning system 200, or bymultiple positioning systems 200, for the additional object 208. Also,where multiple positioning systems 200 are used to track multipleobjects 208, information regarding the position of an object 208determined by one of the positioning systems 208 can be shared withother positioning systems 200.

Aspects of a method for providing a visible target 204 to an operator ofemplacement equipment 210 for use in placing an object 208 in a targetlocation 202 are depicted in FIG. 9. Initially, at step 904, thecoordinates or other geolocation information of a target area 202 for anobject is determined. This can include receiving coordinates in the formof a latitude and longitude, ranges and/or angles relative to a monument226, or other know location. Alternatively, the location of the targetarea 202 can be obtained through input from an operator received througha user input 516. At step 908, the geolocation information is stored inmemory 464.

A projected target 204 is then produced by the positioning system 200(step 912). In accordance with embodiments of the present disclosure,the projected target 204 is produced to outline all or selected portionsof the target area 202. The projected target 204 can be generated withreference to characteristics of the object 208 being placed in thetarget area 202. For example, if the object 208 includes a tripodsupport structure, the projected target 204 can include an outline ofthe desired locations for each foot of the tripod. In accordance with atleast some embodiments of the present disclosure, the positioning system200 can provide information in addition to a line or other indiciamarking a target area 202. For instance, the positioning system 200 cancontinuously or periodically monitor the location of the object 208relative to the target area 202, and can provide relevant informationregarding the alignment, velocity, or other information to the operatorof the emplacement equipment 210. In addition to data, the informationcan include directional guidance, for example in the form of one or moredirectional arrows. Moreover, such arrows can vary in length, forexample to indicate a distance from the target area 202. As a furtherexample, curved or otherwise non-linear arrows can be projected toindicate a preferred path for the object 208 to follow. This informationcan be provided through indicia projected onto the seafloor, onto theobject 208 itself, or onto underwater structures in the vicinity of theobject 208 and/or the target area 202. For instance, additionalinformation can be projected within and/or adjacent an area encompassedby the projected target 204.

In accordance with further embodiments of the present disclosure theprojected target is virtual. In this virtual world the positioningsystem 200 operates to track the true relations between the target area202 and the object 208, and to present a virtual depiction of the targetarea 202, the target indicia 244 and/or the object 208. This virtualinformation could be displayed by a screen of an output device 520included as part of the user interface 504, and could be used, forexample, by a crane operator watching the screen while placing theobject 208 within the target area 202.

At step 916, the object 208 is moved to the target area 202. Next, adetermination can be made as to whether positioning the object 208 inthe target area 202 has been completed (step 920). In accordance with atleast some embodiments of the present disclosure, this can include thepositioning system 200 scanning the object 208 to verify that the object208 is within the target area 202. Moreover, the positioning system 200can verify that the object 208 has a desired orientation or is otherwisecorrectly positioned. In accordance with still other embodiments, thedetermination as to whether placing the object 208 within the targetarea 202 is complete can be performed manually by an operator, forexample by comparing the position of the object 208 relative to thevisible target 204 projected by the positioning system 200. In furtherembodiments, if positioning of the object 208 is not complete (920) thenoperator feedback (step 924) is generated to assist with the next step916. Operator feedback can include directional arrows or guidesprojected onto an underwater object or feature, and/or can be displayedby the user interface 604. It could also include live feedback ofposition, heading, approach velocity, and other information. It can alsoinclude proximity or collision detection warnings. If positioning of theobject 208 has been completed, the process can end.

With reference now to FIG. 10, another undersea scenario including theprojection of a visible target or image 204 by a positioning system 200in accordance with embodiments of the present disclosure is depicted. Inthis example, the object 208 being positioned has at least threepreviously coordinated reference points or targets 244, shown as pointsA, B, and C in the figure. The positioning system 200, in this examplecarried by an underwater vehicle 216 in the form of an ROV, is placed ata location from which the targets 244 on the object 208 are visible, andfrom which the target area 202 for the object 208 is visible, to enablethe positioning system 200 to project a visible target 204.

Aspects of a method for placing an object 208 in a target area 202 in ascenario such as depicted in FIG. 10 are shown in FIG. 11. Initially, atstep 1104, a scan plan is determined. The scan plan can includedetermining a location at which the ROV carrying the positioning system200 should be placed in order to have a view of the object 208 beingpositioned and the target area 202 for the object 208. The ROV 216 canthen be moved to the predetermined location (step 1108). From thatpredetermined location, the positioning system 200 is operated to scanthe object 208 (step 1112). An operator can view the scan data (step1116), for example as presented by a user interface 604, to determinewhether the targets 244 on the object 208 are visible (step 1120). Inaccordance with further embodiments, determining whether the targets 244are visible to the positioning system 200 can be performed by anautomated image recognition process running on the positioning system200 itself, on a related monitoring and control station 504, or on someother device or system.

If it is determined at step 1120 that the location at which theunderwater vehicle 216 has been placed does not enable a view of thetargets 244, the process can return to step 1108, and the underwatervehicle 216 can be repositioned. If the location is good, and thetargets 244 are in view, an area or areas in which a high resolutionscan is performed is selected (step 1124). The selection of an area fora high resolution scan can be made by a human operator selecting thearea through a user interface 604, or through an automated process.

A high resolution scan of the selected area is then performed, and thecentroids of the targets 244 within the scanned area are located (step1128). The locating of the centroids of the targets 244 can be performedby an image recognition process running on the processor 448. Thelocation of the positioning system 200 can then be determined (step1132). As an example, the location of the positioning system 200relative to the object 208 can be determined by performing a three pointresection traverse, in which the location of the positioning system iscalculated from the determined angles subtended by lines of sight fromthe positioning system 200 to the three previously coordinated targets244. Moreover, where the object 208 is itself geolocated, determiningthe location of the positioning system 200 relative to the object 208allows the positioning system 200 to itself be geolocated. Thepositioning system 200 is then controlled to project a visible target204, indicating the target area 202 for the object 208 (step 1136). Thevisible target 204 can continue to be projected until the object 208 hasbeen placed within the target area 202. The process can then end.

With reference now to FIG. 12, still another undersea scenario includingthe projection of a visible target or image 204 by a positioning system200 in accordance with embodiments of the present disclosure isdepicted. In this example, the object 208 being positioned has at leastthree previously coordinated reference points or targets 244, shown aspoints A, B, and C in the figure. In addition, a target stand 222 (ormultiple stands) having a plurality of targets 244, denoted as targetsP₁, P₂, and P₃, affixed thereto, is included. The positioning system200, for example carried by an underwater vehicle 216 in the form of anROV, is initially placed at a first location 1204 from which the targets244 on the object 208 are visible, and from which the targets 244 on thetarget stand 222 are visible. The ROV carrying the positioning system200 can then be moved to a second location 1208 from which the targetarea 202 for the object 208 is visible, to enable the positioning system200 to project a visible target 204.

Aspects of a method for placing an object 208 in a target area 202 in ascenario such as depicted in FIG. 12 are shown in FIG. 13. Initially, atstep 1304, a scan plan is determined. The scan plan can includegenerally determining a first location at which the ROV carrying thepositioning system 200 should be placed in order to have a view of theobject 208 being positioned and of a target stand 222 located in thevicinity of the object 208, and a further location at which the ROVcarrying the positioning system 200 should be placed in order to providea view of the target area 202 for the object 208. The ROV 216 can thenbe moved to the first predetermined location, from which the object 208is or should be visible (step 1308). From that first location, thepositioning system 200 is operated to scan the object 208 (step 1312).An operator can view the scan data, for example as presented by a userinterface 604 (step 1316), or an automated process provided with thescan data can be executed, to determine whether the targets 244 on theobject 208 are visible (step 1320). If the targets 244 are not in view,the process can return to step 1308, and the underwater vehicle 216 canbe repositioned. If the location is good, and the targets 244 are inview, an area or areas in which a first high resolution scan isperformed is selected (step 1324). The selection of an area for a highresolution scan can be made by a human operator selecting the areathrough a user interface 604, or through an automated process.

A high resolution scan of the selected area is then performed, and thecentroids of the targets 244 within the scanned area are located (step1328). The locating of the centroids of the targets 244 on the object208 can be performed by an image recognition process running on theprocessor 448. The location of the positioning system 200 can then bedetermined (step 1332). As an example, the location of the positioningsystem 200 relative to the object 208 can be determined by performing athree point resection traverse. Moreover, where the object 208 isgeolocated, determining the location of the positioning system 200relative to the object 208 allows the positioning system 200 to itselfbe geolocated.

At step 1336, the positioning system 200 is operated to scan the targetstand 222 from the first location. An operator viewing the data or anautomated system can then select an area encompassing the targets 244 onthe target stand 222 (step 1340), and a high resolution scan of theselected area can then be performed, from which the locations of thetarget 244 centroids can be determined (step 1344), thereby allowingthose targets 244 to be geolocated. At step 1348, the positioning system200 is moved to a second location, for example by repositioning the ROVcarrying the positioning system 200. The target stand 222 is thenscanned (step 1352). An operator or an automated system can then viewthe scan data (step 1356), to determine whether the targets 244 on thetarget stand 222 are visible (step 1360). If the targets 244 are not inview, the process can return to step 1348, and the underwater vehicle216 can again be repositioned. If the location is good, and the targets244 are in view, an area or areas in which a first high resolution scanis performed is selected (step 1364). The selection of an area for ahigh resolution scan can be made by a human operator selecting the areathrough a user interface 604, or through an automated process.

A high resolution scan of the selected area is then performed, and thecentroids of the targets 244 on the target stand 222 are located (step1368). The locating of the centroids of the targets 244 on the targetstand 222 can be performed by an image recognition process running onthe processor 448. The location of the positioning system 200 can thenbe calculated from the previously determined locations of the targets244 on the target stand 222 (step 1372), for example by performing athree point resection traverse. As can be appreciated by one of skill inthe art after consideration of the present disclosure, additional targetstands 222 can be used to enable an object 208 to be moved a relativelylarge distance from a first known location to a target area 202, even inturbid water conditions. The positioning system 200 is then controlledto project a visible target 204, indicating the target area 202 for theobject 208 (step 1376). The projection of the visible target 204 can becontinued until the object 208 is positioned within the target area 202.

As described herein, a positioning system 200 can incorporate a lidarsystem 308 that is implemented as a single spot sensor system, such as ascanning lidar, or a lidar that receives and senses returns frommultiple points within a scene simultaneously. In a single spot sensorsystem, measurements from different points within a scene can be made atvirtually the same time, by sequentially pointing the lidar system 308of the positioning system 200 at different points within the scene in anautomated fashion. In a flash sensor system, measurements from differentpoints within a scene can be made at the same time (i.e. multiplemeasurements can be obtained from returns generated from a single pulseof light), with returns received at different pixels within the sensorcorresponding to different azimuth angles and elevation angles relativeto the lidar system 308. The positioning system 200 can be mounted on anROV, AUV, tripod, monument, cage, or other subsea structure. In at leastsome embodiments, a cage or frame 224 of a positioning system 200 canitself comprise an underwater structure 304 and can provide a platformwith numerous selectable functions. This can include the incorporationof batteries and a power control system that allows for long-termautonomous deployment. The positioning system 200 can also provideadditional capabilities, including, but not limited to, data storage andbackup, temperature sensors, depth sensors, salinity sensors, otherchemical sensors, and communication devices. The positioning system 200can also provide timing signals between multiple sensors to timesynchronize the data collection of those sensors. Examples ofcommunication devices include wired electrical or optical systems, aradio frequency, free space optical, or acoustic devices. Communicationscan be with ROVs, AUVs, resident vehicles, other intelligent structuresin the field, or the surface. The positioning system 200 can store data,compress and send out data samples, or auto process data to look forchange detection and send alarms signals when change is detected.Moreover, a positioning system 200 can provide power, data storage, andcommunications capabilities to other monitoring devices or positioningsystem 200, for example to allow for monitoring at different angles orover an increased field of view. Alternatively, or in addition, thepositioning system 200 can be connected to the local infrastructure forpower and/or communications.

In at least some embodiments of the present disclosure, a human operatoror user interacts with the positioning system 200 through a monitoringand control station 504 that is in operative communication with thepositioning system 200. The user can control the field of regard of thepositioning system 200 by entering control commands through a user input516 to direct a movable platform or vehicle 216 carrying the positioningsystem 200, and/or to direct a pan and tilt head to which a lidar system308 or the positioning system 200 itself is mounted. In addition, realtime or near real-time feedback regarding the field of regard of thepositioning system 200 can be provided to the user through the useroutput 520. Moreover, the feedback provided by the user output 520 canbe in the form of a two-dimensional image obtained by a camera 328, avisualization of point cloud data obtained by a lidar system 308, or asynthesis of two-dimensional and three-dimensional data.

In accordance with still other embodiments of the present disclosure, apositioning system 200 can operate autonomously or semi-autonomously.For example, in an autonomous mode, the positioning system 200 can scana scene to obtain point cloud data of an area encompassing a target area202 and can execute software to generate a projected target 204 toprovide a visual indication of the target area 202, to assist anoperator in accurately placing an object 208 in the target area. In asemi-autonomous mode, a user can provide direction to the positioningsystem 200, such as manually defining the location or othercharacteristics of the projected target 204.

Where multiple positioning systems 200, or where multiple monitoring 304and/or projection systems 406 are employed, information from some or allof the multiple systems can be synthesized in a common control center orin an underwater component of the system. Also in embodiments in whichmultiple positioning systems 200 are included, some or a plurality ofthe positioning systems 200 can be operated to project a visible target204 to aid in the placement or guidance of equipment or other objects208. In this scenario, for example as depicted in FIG. 8, multiplepositioning systems 200 could start by monitoring the location of thesame object 208 in order to improve the location and heading estimatesof the object 208. One can then determine by trial and error or byalgorithm which positioning system or systems 200 are providing the mostaccurate data due to their perspective orientation relative to theobject 208. The remaining positioning system or systems 200 can then bededicated as the projection system 406. This division of tasks betweenpositioning systems 200 can be modified as the object 208 approaches thetarget location 202. Alternatively, or in addition, a dedicatedprojection system 406 that receives location information from amonitoring system 304 can be included. In accordance with still otherembodiments of the present disclosure, targets, such as the 2-D targets244, three-dimensional spherical targets 240, prisms, or other targetindicia or structures can be attached to underwater objects 208, targetstands 222, or monuments 226 and can be detected by the positioningsystem 200 for use in obtaining absolute and/or relative locationinformation.

Embodiments of the present disclosure can additionally utilize multiplemonitoring system 304 and/or projection system 406 componentssimultaneously. For example, multiple, geo-located, monitoring systems304 can be used to provide information regarding the location andheading of a subsea object 208. Each monitoring device 304 can shareinformation regarding its own geolocation with the other monitoringdevices 304 to provide redundancy and high accuracy. Alternatively, apositioning system 200 or a monitoring system 304 with a knowngeolocation can provide location information to another positioningsystem 200 or monitoring system 304. In accordance with still otherembodiments of the present disclosure, a monitoring system 304 can beoperated to take a plurality of range, intensity, and angle, anglemeasurements from a monitored subsea object, and can average thosemeasurements, to provide a higher level of accuracy as compared tomeasurements taken using a single or smaller number of scans. Inaddition, multiple projection systems 406 can be used to ensure that anunobstructed visible target is presented to an operator of emplacementequipment.

As can also be appreciated by one of skill in the art afterconsideration of the present disclosure, various functions can bedistributed amongst different components of a positioning system 200 ordifferent connected systems or devices. For example, the processor 448located within an underwater pressure vessel 402 of a positioning system200 can execute application software 463 that controls an associatedlidar device 308 to obtain raw point cloud data comprising azimuthangle, elevation angle, range, intensity, and timestamp information. Theinformation generated by such onboard processing can then be transmittedby the communications interface 468 to a monitoring and control station504. Alternatively or in addition, onboard processing performed by thepositioning system 200 can provide automatic notifications or alarmsthat are transmitted to the monitoring and control station 504 or otherfacility. The monitoring and control station 504 receives the pointcloud data, notifications, alarms, or other information transmitted bythe positioning system 200 through a communication interface 528, andstores the point cloud data 540 in data storage 524. The processor 508can then execute system application software 532 to present avisualization of the point cloud data through a user output device 520.The processor 508 can further execute system application software 532 toreceive input from the user regarding the generation of a projectedtarget 204 that is passed to the positioning system 200. In accordancewith still other embodiments of the present disclosure, processing ofpoint cloud data can be performed by the monitoring system 304 itself,by servers or control stations provided in place of or in addition tothe monitoring and control station 504, or in various combinations.

Optical targets can be affixed to undersea structures to enhance theidentification and locating of such structures by a monitoring device.The optical targets can be two or three dimensional. In addition,different targets can have different optical characteristics, to allowthe different targets is to be distinguished from one another by themonitoring device. The optical targets can vary characteristics of thelight that is reflected back to the monitoring device. Suchcharacteristics can include the intensity, pattern, frequency, phase, orpolarization of the light. In addition, the targets can encodeinformation using barcodes, holograms, human perceptible indicia, or thelike.

Particular examples of applications of the disclosed positioning systemsand methods include the placement, removal, or manipulation of any andall equipment installed underwater for an oil or gas field, wind farm,or other structure, and the accompanying seabed. This includes, but isnot limited to, an entire subsea tree system, subsea manifold, pipelineend termination (PLET), blowout preventer (BOP), pipelines and flowlines, anchors, risers, touch down points, suction piles, chains, slipjoints, subsea processing systems, and the interconnectivity jumpersfrom the well to the surface delivery connection and surroundingseafloor. The described systems and methods increase the efficiency ofinstallation and monitoring capability during installation, drilling,reservoir stimulation, construction, well intervention, riserless wellintervention, well pressure testing, and during plug and abandonmentoperations. The described methods and devices utilize one or morenon-touch subsea optical systems (including laser systems) for subseawell and subsea infrastructure installations, measurements andmonitoring. Monitoring of undersea systems can include monitoring shiftsin location over time.

In accordance with at least some embodiments of the present disclosure,the technology encompasses:

(1) A method for placing an object at a desired location in anunderwater environment, comprising:

determining a target location for an object, wherein the target locationis in the underwater environment;

operating a positioning system to project a visible target at the targetlocation, wherein the positioning system is in the underwaterenvironment.

(2) The method (1), further comprising:

geolocating the positioning system, wherein the target location for theobject is geolocated relative to the positioning system.

(3) The method of (2), wherein geolocating the positioning systemincludes operating a laser system to geolocate the positioning system.

(4) The method of (2) or (3), wherein the positioning system isgeolocated by detecting a location of a monument, structure, or featurerelative to the positioning system.

(5) The method of any of (2) to (4), wherein the positioning system isgeolocated using underwater acoustic beacons with or without an InertialNavigation Unit in conjunction with the positioning system.

(6) The method of any of (3) to (5), wherein a light source of the lasersystem produces light at a visible wavelength, and wherein the visibletarget is produced using light from the light source of the lasersystem.

(7) The method of any of (1) to (6), further comprising:

-   -   a video system, wherein the video system provides a view of the        visible target to an operator of at least one of a crane and an        underwater vehicle, and wherein the at least one of the crane        and the underwater vehicle is used to place the object at the        desired installation location.

(8) The method of any of (1) to (7), further comprising:

operating the positioning system to determine a location of the objectrelative to the target location.

(9) The method of any of (1) to (8), wherein the projected visibletarget at the target location is a virtual target projected onto aremote monitor in addition to a virtual object projected onto the sameremote monitor.

(10) The method of (9), wherein the virtual target and object arecontained in computer memory and are used by an autonomous system foraccurate placement of the object.

(11) The method of any of any of (1) to (8), further comprising:

moving the object towards the target location.

(12) The method of any of (1) to (8), further comprising:

determining a position and orientation difference between the object andthe target location;

outputting the determined position and orientation difference to anoperator of emplacement equipment being used to move the object towardsthe target location.

(13) The method of (12), wherein the operator of emplacement equipmentis an automated system.

(14) The method of (12) or (13), further comprising outputtingdirectional cues, approach velocities, proximity warnings, and collisionalarms to an operator of emplacement equipment being used to move andorient the object at the target location.

(15) The method of (14), wherein the operator of emplacement equipmentis an automated system.

(16) The method of any of (1) to (15), wherein the target location forthe object is received as an absolute geographic location.

(17) The method of any of (1) to (16), wherein the visible target is atleast a partial outline of the target location.

(18) The method of any of (1) to (17), wherein the visible targetindicates a desired installation location of the object.

(19) The method of any of (1) to (18), wherein after the object isplaced, the positioning system measures and reports the final touchdownspeed, along with the final location and how much these vary from theideal location.

(20) The method of any of (1) to (8), wherein after the object isplaced, the positioning system captures and produces a final point cloudof seabed around the object for “as deployed” conditions to compare withfuture scans for scour or dredging.

(21) The method of any of (1) to (20), wherein a plurality ofpositioning systems are used wherein each positioning system has a knownlocation, wherein each positioning system is operable to determine alocation of an object relative to the positioning system, wherein eachpositioning system communicates location information to at least oneother positioning system, and wherein one or more positioning systemsproject a visible target at the target location.

(22) The method of (21), wherein each positioning system communicateslocation information to at least one other positioning system and theobject.

(23) The method of (21) or (22), further comprising: a plurality ofobjects, wherein a location of each of the object is determined by oneor more of the positioning devices.

(24) The method of any of (1) to (23), wherein reference indicia areplaced on the object to accurately determine its position andorientation with respect to the target location.

(25) The method of any of (1) to (24), wherein the positioning system isgeolocated by detecting a location of a monument, structure, or featurerelative to the positioning system.

(26) The method of (24) or (25) wherein at least one instance of thereference indicia is placed on the monument, structure, or feature.

In accordance with further aspects of the present disclosure, thetechnology encompasses:

(27) A system for facilitating the placement of objects in an underwaterenvironment, comprising:

a light source;

an image projection device;

memory, wherein the memory stores instructions for operating the lightsource and the image projection device, and wherein the memory furtherstores data regarding a target location; a processor, wherein theprocessor is operable to execute the instructions for operating thesystem, and wherein the instructions cause the light source and theimage projection device to project a visible target within the targetlocation.

(28) The system of (27), wherein the light source and the imageprojection device are operated to obtain point cloud data and togeolocate the system.

In accordance with still other aspects of the present disclosure, thetechnology encompasses:

(29) A system for facilitating the tracking of objects in an underwaterenvironment, comprising:

a light source;

a device for collecting point cloud data;

memory, wherein the memory stores instructions for operating the lightsource and the device, and wherein the memory further stores dataregarding a target location;

a processor, wherein the processor is operable to execute theinstructions for operating the system, and wherein the instructionscalculate the position and orientation information of the object toassist movement of the object to a target location.

(30) The system of (29), wherein the underwater object is one or moreunderwater vehicles and the system assists the vehicle with movement toa target location, automated docking, obstacle avoidance, valveoperations, and valve observations.

(31) The system of (30), wherein the system provides zero velocitypositional updates to the vehicle navigation system without the need formechanical docking.

The foregoing discussion has been presented for purposes of illustrationand description. Further, the description is not intended to limit thedisclosed systems and methods to the forms disclosed herein.Consequently, variations and modifications commensurate with the aboveteachings, within the skill or knowledge of the relevant art, are withinthe scope of the present disclosure. The embodiments describedhereinabove are further intended to explain the best mode presentlyknown of practicing the disclosed systems and methods, and to enableothers skilled in the art to utilize the disclosed systems and methodsin such or in other embodiments and with various modifications requiredby the particular application or use. It is intended that the appendedclaims be construed to include alternative embodiments to the extentpermitted by the prior art.

What is claimed is:
 1. A method, comprising: determining a targetlocation for an object, wherein the target location is in an underwaterenvironment; projecting a visible target at the determined targetlocation; and placing the object at the target location.
 2. The methodof claim 1, wherein the visible target is projected from a positioningsystem, the method further comprising determining a location of thepositioning system, wherein the target location for the object isdetermined relative to the location of the positioning system.
 3. Themethod of claim 2, wherein determining the location of the positioningsystem includes operating a light-based metrology system to determine adistance from the metrology system to a stationary structure having aknown location.
 4. The method of claim 3, wherein a plurality of targetsare affixed to the stationary structure.
 5. The method of claim 1,wherein the visible target is projected from a positioning system, andwherein the positioning system is carried by an underwater vehicle. 6.The method of claim 1, wherein the positioning system is on the object,wherein the visible target is projected from the positioning system, themethod further comprising using the positioning system to determine alocation of the object relative to a location of an underwater monument,underwater structure, or underwater feature.
 7. The method of claim 1,wherein the object is placed at the target location by emplacementequipment.
 8. The method of claim 1, wherein a location of the object isdetermined relative to one or more stationary structures, the methodfurther comprising: determining a position and orientation differencebetween the object and the target location.
 9. The method of claim 8,wherein the one or more stationary structures includes at least onetarget stand.
 10. The method of claim 1, wherein the target location isdetermined by determining a location of an underwater monument,underwater structure, or underwater feature relative to the targetlocation.
 11. The method of claim 1, wherein determining a targetlocation includes determining a geolocation of the target location. 12.The method of claim 1, wherein the visible target is at least a partialoutline of the target location.
 13. The method of claim 2, furthercomprising: after the object is placed at the target location, operatingthe positioning system to determine a location of the object asdeployed.
 14. A method, comprising: determining coordinates of a targetlocation; generating a virtual target indicating the target location;moving an object toward the target location using emplacement equipment;monitoring a location of the object relative to the target location; andplacing the object at the target location.
 15. A system, comprising: alight source; transmit and receive optics; a scanning device, whereinthe scanning device directs light generated by the light source andreceived from the transmit and receive optics toward a target location;a receiver, wherein light reflected from the target location is receivedat the receiver; memory, wherein the memory stores instructions foroperating the system, including the light source, the scanning device,and the receiver; and a processor, wherein the processor is operable toexecute the instructions for operating the system, wherein in a firstmode of operation the light source and scanning device are operated toproject as a visible target at the target location, and wherein in asecond mode of operation the light source, scanning device, and receiverare operated to determine a range to the target location.
 16. The systemof claim 15, wherein determining a range to the target location includesoperating the light source, the scanning device, and the receiver toobtain point cloud data that includes three-dimensional locations ofpoints within an area of an underwater scene that includes the targetlocation.
 17. The system of claim 15, further comprising: emplacementequipment, wherein the emplacement equipment is operable to place anobject at the target location.
 18. The system of claim 17, wherein theemplacement equipment includes at least one of a crane, an underwatervehicle, or a diver.
 19. The system of claim 17, further comprising: avideo system, wherein the visible target is viewed by an operatorthrough the video system.
 20. The system of claim 15, furthercomprising: an inertial navigation unit, wherein the inertial navigationunit provides information regarding a location of the system.